Problem: Given the line: $-7x + 9y = 81$ What is the $y$ -intercept?
Explanation: The $y$ -intercept is the point where the line crosses the $y$ -axis. This happens when $x$ is zero. Set $x$ to zero and solve for $y$ $ -7(0) + 9y = 81 $ $9y = 81$ $\dfrac{9y}{9} = \dfrac{81}{9}$ $y = 9$ The line intersects the $y$ -axis at $(0, 9)$. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${10}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${\llap{-}10}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${10}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${\llap{-}10}$ $(0, 9)$